Producing high vacuums.



He. swans. Patented 0st. 30, mos. .1. w, SEBWELL.

PRUDUClNG H552! VACUUMS.

(Application ill-2d A'xg. a1, 1899.)

(Ho Model.)

\Mtnesses. J nventor.

UNITED STATES/ ATENT O FFI-CE,

JOHN W. HOWELL, OF NEWARK, NEW JERSEY, ASSIGNOR TO THE GENERAL ELECTRICCOMPANY, OF NEW YORK.

PRODUClNG HIG H VACUUMS,

srncmoa'non forming part of has Patent No. 660,816, dated October so,1900.

Application 11106 August 31, 1899- I Serial No. 729,076- (No specimens.)

To all whom it'mayjconcerm' Be it known that I, JOHN W. HOWELL, a citi-'zen of the United States, residing at Newark, county of Essex, State ofNew Jersey, have invented certain new and useful Im provements inProducing High Vacuums, (Case ing a High vacuum ata lowercost than by.any method heretoforeproposedwith'which' No. 1,376,) of which thefollowing is a speci-' fication.

My invention relates to the production of high vacuums, and isparticularly adapted for service in connection with the exhaustion ofincandescentelectric lamps. By the methods commonly employed in themanufacture of incandescent lamps,'gases,including air and hydrocarbongases, are trapped or occluded "in the filament and itsjoints andmoisture is deposited on the walls-of the bulb, the-last traces of whichare exceedingly difficult to ,remove and in the case of high-voltagelamps require for satisfactory life of the filamenta long-continuedexhaustion by'the pump.

A good vacuum may be established by mechanicalpumps, the design ofwhichis fa.-

miliar to those skilled in the art, but at the expense of considerabletime-for exhaustion. Methods have been designed for promoting rapidityof exhaustion and the. removal of the last traces of deleterious gases,so as produce a. satisfactory vacuum, by introducing within the bulbneutral or inert gases and then again continuing the exhaustion; butdifliculty is experienced-in providing an inert gas which issufficiently free from impurities to afford a satisfactory result. Othermethods have been proposed for acting chemically upon the residual gasesoccluded i'hthe fila-f ment and its joints by vaporizing. solids orliquids capable of combining with them and removing the products of thereaction My process afiords a imeaus' fo'r' establish- ,I am familiar. 1

I carry out my invention by producing a preliminary exhaustion by theaid of apump, for which I prefer to employ a good type ofand thencontinuing the exhaustion with the filament brought to incandescence. Ithen admit to the bulb a determinate'volume of phosph'in .orphosphoreted hydrogen gas at ordinary atmospheric temperatures, whichacts not only mechanically as a vehicle for assisting the exhaustion ofthe residual gases byawashing-out action, but establishes a sul'tantcheapening of the'cost of the lamp.

This decrease in theexpe'nse is an incident principally of the gaseoustreatment by which a gang or group of lamps may be simultane ouslysubjected to the action of the gas, and I an attendant may thereforemanage several independent machines or'exhausting devices.

No particularorganizatien of apparatus is required to carry out myinvention, except provisions for pumping off the air or gases and forintroducing the phosphin. It will,

. however,'greatly facilitate an increased 'output per'operator tofollow the usual plan of v connecting with each pump an exhaustiomtube'haviug a plurality of air-tight sockets or openings to receive thestems of a group of lamps. The arrangement of'such apparatus and t-heconstruction of the lamp are so known form of lamp-bulb inwhicha tubular;stem 1 isleft after the pillar carrying thefilament has been sealedinto the-neck of the lamp and by which the exhausting processes areconducted, after which the.bulb 2 is sealed ofi near its junction withthe stem. and the lampis ready for the market.

I In practicing my process the stem 1 isconnected by an elastic joint inthe usual manner with a pump, for. which I prefer to employ a mechanicalpump, and agroup of eight or more lamps are similarly connected to theroe same pump. A rough exhaustion is then made and the usual tests fordefects in the is then raised to a high temperature by pass- "quantityofphosphoreted hydrogen is then lamp structure or filament-joints made byconnecting with-J an induction-coil or other source of high-tensioncurrent. The filament ing a current through it and allowed to burn ashort time to allow the pump to exhaust the occluded gases. A definitegraduated admitted to the group of lamps by means of phosphoretedhydrogen and the products of its reaction: upon the residual gases willhave beenwil-hdrawn. The phosphoreted hydrogen acts as a menstruu m orvehicle to carry off the residual gases by diffusing throughout the bulbandmixing'with them and also reacts chemically upon such occluded gasesas are capable of reacting with it.

I prefer to generate the phosphoreted hydrogen by heating phosphorus ina-solution of caustic potash, though other methods, such as heating itwith milk of lime or mixing phosphid of calcium with water, may beemployed. In any of these processes the'phosphoreted hydrogen (PH is notchemically pure, but carries with it more or less vapor of the liquidphosphid of hydrogen, (P ll which has a great affinity for certaingases, and especially oxygen at reduced pressures. I believe thehydrocarbons present are decomposed by the action, of the phosphoretedhydrogen, which takes on an additional atom or atoms of hydrogen at theexpense of the hydrocarbon gases in the bulb, and therebyfacilitates an-almost complete exhaustion of the residual gases, The heating of thelamp both internally and externally duringthe operation drives elf anyfilm of moisture which may be deposited upon the inner wall of the globeor other parts, which is removed with the gas by the pump.

What I claim as new, and desire to secure by Letters Patent of theUnited States, ta-

1. The process of producing high vacuums, consisting in exhausting airor other gas from the inclosnre, then admitting phosphoreted hydrogenand again exhausting the iltclosure. 2. The process of producing a highvacuum in an incandescent lamp, consisting in first exhausting the airand other gases from thebulb, then admitting phosphoreted hydro-' gen,then again exhausting the bulb.

3. The process of producing a high vacuum in an incandescent lamp,consisting in exhausting the air and other gases from the bulb in whichthefilament is mounted, then admitting a-compound gaseous at ordinaryatmospheric temperatures having an afiinity for the residual gases inthe bulb, then exhausting the bulb. 7' 4. The process of producinga highvacuum in an incandescent lamp, consisting in ex-.

hausting the air and other gases from the.

bulb, heating the lamp, admitting a determinate quantity of phosphoretedhydrogen, I

then exhausting and sealing oti the lamp.

. 5. The processof prodncingahigh vacuum in an incandescent lamp,consisting in first exhausting the bulb, then heating the filament andwalls of the lanip, then admitting phosphoreted hydrogen to the bulb,then again exhausting.

In witness whereof I havehereunto setmy hand this 23d day of August,1899.

JOHN W. HO WELL.

Witnesses:

A. R. DENMAN, V IRVING T. TYLER.

